Control system for fluid operated mechanism



Feb. 10, 1959 J. w. TIMMERMAN 2,873,084 CONTROL SYSTEM FOR FLUIDOPERATED MECHANISM Original Filed Jan. 2, 1952 2 Sheets-Sheet 1 M 75.WWW

Feb. 10, 1959 J. w. TIMMERMAN CONTROL SYSTEM FOR FLUID OPERATEDMECHANISM 2 Sheets-Sheet 2 Original Filed Jan. 2, 1952 0 6 a 6 V Z 6 7 9a a mm a m v w$vvw 3 mmmmwwwwmm W vvv vfl 0 5 0 v v a 9/ n 5 w 4 9 u 13. w g k ,0 a 15m w Em; W a m i 2 2 M 0 k3 a 4 a A United States PatentCONTROL SYSTEM FOR FLUID OPERATED MECHANISM Original application January2, 1952, Serial No. 264,370. Divided and this application March 27,1953, Serial No. 345,060

8 Claims. (Cl. 251-239) This invention relates to fluid operatedmechanisms and more particularly to control arrangements for fluidoperated motors.

Heretofore control arrangements for fluid operated motors have beencomplicated and expensive to manufacture. Therefore, it is desirable toprovide a control arrangement which is simple in design and dependable.The control arrangement should-be responsive to the motor position so asto eliminate the possibility of a complete control system operationbefore the motor has moved a predetermined distance.

In a preferred embodiment of the invention claimed a new and improvedcontrol system for fluid operated mechanisms is provided whichcomprises, among other things, a valve connected to a source of fluidunder pressure, means for holding the valve closed, solenoid means forcontrolling the valve comprising a core, a coil, an armature, and a polemember movable from a first position to a second position to shift theflux path through the core. The armature of the solenoid means uponenergization of the coil actuates the holding means to release thevalve. Pneumatic means are further provided to shift the pole memberfrom the first position to the second position. The pole member when inthe second position locks the valve closed as long as a predeterminedcurrent flows through the coil.

It is therefore one object of the present invention to provide a new andimproved control system in which the control arrangement is responsiveto movement of a fluid motor in two directions.

Another object of this invention is to provide a new and improvedsolenoid control mechanism in which the flux paths are shifted by afluid means.

A further object of this invention is to provide a new and improvedcontrol valve which is simple in design and dependable under alloperating conditions.

Objects and advantages other than those set forth will be apparent fromthe following description when read in connection with the accompanyingdrawings, in which:

Fig. 1 is a diagrammatic view partly in elevation of a circuitinterrupting system embodying the present invention; and

Fig. 2 is an enlarged view in axial cross section through a pneumaticcontrol valve illustrated in Fig. 1.

Referring more particularly to the drawings by characters of reference,Fig. 1 illustrates a circuit breaker including as a constructive elementthereof a reservoir 6 constituting a source of supply of fluid underpressure, which will be assumed herein to be compressed air suppliedfrom a suitable compressor (not shown). Although in general, circuitbreakers of the type herein considered are provided with a plurality ofsimilar pole structures, one for each phase of a polyphase electriccircuit, only 2,873,084 Patented Feb. 10, 1959 an electric circuitthrough terminal studs 9 and 10. The arcing contacts are mounted toengage within an arcing chamber 11 which is aligned with an arc chute12. The arcing chamber 11 is axially aligned with a hollow insulator 13which provides a connection between reservoir 6 and arcing chamber 11through a suitable blast valve 14 for directing a blast of arcextinguishing fluid under pressure between the arcing contacts andthrough the arcing chamber 11.

The blast valve 14 is actuated by a fluid motor 15 and controls a blastinlet port 18. Motor 15 comprises a cylinder 19, a blast valve crackingpiston 20, a piston rod 21, a spring 22, and an inlet port 24.

A solenoid operated valve 25 opens automatically if a fault currentoccurs on the power circuit controlled or if valve 25 is manuallyactuated by a pushbutton arrangement 26. Valve 25 controls the flow offluid under pres sure from reservoir 6 through a pipe line 27, a valve25, pipe line 28, a three way valve 29, and inlet port 24 of cylinder 19to the blast valve cracking piston 20 of fluid motor 15.

Valve 29 is connected by linkage 30 to a lever 51 mounted on a rockingshaft 31. A linkage 32 connects rocking shaft 31 with the movable sickleshaped arcing contact 8. If arcing contact 8 is in the closed positionthereof, valve 29 is in such an angular position as to admit compressedair to cylinder 19 through inlet port 24.. Upon opening of valve 25compressed air from the reservoir 6 is admitted to a pipe line 35 whichis connected to a pipe line 44 and an inlet port 36 of a fluid motor 45.Near the end of the opening stroke of the breaker the three way valve 29is rotated approximately ninety degrees clockwise and in so doing dumpsto atmosphere the air from the right side of piston 20 of fluid motor15.

Fluid motor 45 comprises a cylinder 47, a piston 48 having a piston rod49 movable therewith and connected through a connecting rod 50 and acrank 51 to shaft 31. Motor 45 is provided with a dumping valve 52 whichreleases pressure above piston 48 at or near the end of its upwardstroke. Dumping valve 52 is biased against its valve seat 53 by a spring54. Dumping valve 52 is provided with ports 55 which are controlled by aplate 56 biased in port closing direction by a spring 57.

Shaft 31 is provided with a cam 60 which upon rotation of shaft 31 incontact opening direction releases a lever arm 61 which in turn releasesa compressed spring 62; Spring 62 acts on piston rod 21 to maintainblast valve 14 in its open position, even upon dumping of air from thehigh pressure side of piston 20.

Closing of the arcing contacts is initiated by energizing a solenoidoperated valve 63 which is substantially identical to valve 25. Valve 63connects reservoir 6 to a fluid motor 64.

Fluid motor 64, through the intermediary of linkage 59 causes rotationof shaft 31 to close the arcing contacts 7, 8. Motor 64 comprises a'cylinder 65, a piston 66, a dump valve 67, valve seat 68, spring 69,valve ports 70, inlet port 71, and outlet port 72.

The solenoid operated valves 25 and 63 are substantially identical sothat a description of only one valve will be set forth. Valve 25comprises a casting forming a cylinder 80 provided with a fluidadmission opening or port 81 and with an exhaust opening or port 82.Port 81 is conone such pole structure or pole unit is shown in thefigure and the circuit breaker will be described in detail as if it wereof the single pole unit type.

The circuit breaker comprises a fixed arcing contact 7 and a cooperatingmovable arcing contact 8 connected in within a casting 85 which isinserted in cylinder 80. A spring 86 biases valve 84 to valve closedposition. Valve 84 is provided with a throttling tip 87 which provides adefinite piston area. A small amount of air through the pilot valve 84lifts the pilot disk or tip 87 high enough against the action of spring86 to make the overall diameter of piston 88 effective in lift againstspring 86. Piston 88 is fitted into casting 85 so as to provide apassage of predetermined cross section for the flow of air from thelower to the upper side of the piston. Piston 88 has the upper sidethereof vented to atmosphere through a plurality of vents 89. Aresilient sealing material 90 is arranged within piston 88 to form atight seal when the pilot valve 84 is closed. When the main valve member83 is moved away from annular valve seat 120 so as to provide a directpassageway between ports 81 and 82 a valve member 121 connected topiston operated valve member 83 by a stern 122 closes opening 123 toprevent the escape of air to atmosphere through opening 123.

The pilot valve 84 is locked closed by a spring biased lever arm 91which abuts against a push rod 92. Push rod 92 abuts against the pilotvalve stem. Lever arm 91 is pivotally mounted at 93 and is arranged tobe secured at 94 to an armature 95 of a solenoid 96. Solenoid 96 furthercomprises a coil 97 and a core or casting 98 of paramagnetic material.

Spring 101 biasing lever arm 91 in valve closing direction is strongenough to hold the pilot valve closed once it is closed but is notstrong enough to close the pilot valve once it is sealed opened.

Casting 98 provides at the lower end thereof a cylinder 102 ofnonmagnetic material which is fitted with a piston 103 of paramagneticmaterial. Piston 103 forming a part of a magnetic pole member 105 isbiased to its lower position by spring 104 but when actuated upwardmoves magnetic pole member 105. Pole member 105 actuates armature 95upward and rotates counterclockwise lever arm 91. Lever arm 91 thenlocks pilot valve 84 in closed position.

Casting 98 includes members 99 and 100 arranged one at each end ofcylinder 102 providing pole surfaces 111 and 112 for magneticallylocking the piston 103 in one of two positions.

Piston 103 of valve mechanism 25 may be actuated by the fluid underpressure in cylinder 47 of fluid motor 45 through a port 73 and a pipeline 106. Piston 103 of valve 63 may be actuated by fluid under pressurefrom cylinder 65 of fluid motor 64 through a pipe line 107 or from fluidunder pressure in pipeline 35 through a pipe line 108.

A manual emergency pilot valve tripping mechanism 26 is provided foropening the main valve member 83, if so desired. Mechanism 26 comprisesa pair of toggle arms 113 and 114 which are arranged to collapse inonedirection only, a pair of springs 115 and 116 arranged on a pull rod 117and balanced one against the other with the toggle arm 114 arranged inbetween them. The toggle arms 113 and 114 are manually held rigid andpivoted about an axis to actuate the lever arm 91 to release the pilotvalve 84 and which collapses to return to their original position whenthe normal pull rod 117 is released. When the pull rod is actuated,spring 115 is compressed enough to overcome spring 101, and the rollermounted on the toggle arms depresses lever 91 to allow the pressure ininlet port 81 to open the pilot valve. Spring 115 then snaps the togglelinkage out of the way of the lever arm 91. Release of the pull button118 arranged on rod 117 causes the toggle linkage to break and ride upover the lever arm 91 and reset for subsequent trip operations.

Upon the occurrence of a fault condition on the power circuit, solenoidcoil 97 of the valve 25 is energized. Armature 95 is actuated to rotatelever arm 91 clockwise about its pivot point 93 to unlock the pilotvalve 84. If the fluid pressure in reservoir 6 is below a predeterminedvalue the leakage of air past main valve member 83, pilot valve 84 andpiston 88, will not be enough to lift the pilot valve 84 appreciablyfrom its valve seat. At a predetermined reservoir pressure the leakageof air past main valve member 83 creates a pressure between main valvemember 83 and pilot valve 84 great enough to lift the tip 87 of pilotvalve 84 to a point where the rate of flow around tip 87 is great enoughto build up pressure under piston 88 to raise and snap the pilot valve84 to its open position and to hold it open. The pressure between mainvalve member 83 and piston 88 will be reduced to a predetermined lowvalue, thus causing the pressure on the upstream side of main valvemember 83 to actuate member 83 to valve open position and to hold itopen. The leakage of air past member 83 when in its open position isstill great enough to hold open the pilot valve 84. Spring 86 has enoughforce to hold the pilot valve closed, but not enough force to close itonce the pilot valve is sealed !open.

The blast of air passing through casting flows through pipe line 28,three way valve 29, inlet port 24 to fluid motor 15. The actuation ofpiston 20 under the force of the fluid under pressure from inlet port 24cracks the blast valve 14 open. Compressed air is admitted through pipeline 35 and pipe line 44 to fluid motor 45. Air under pressure passesthrough ports 55 and actuates plate 56 downward against the bias ofspring 57. Fluid under pressure upstream of piston 48 actuates piston 48downward causing piston rod 49 to rotate shaft 31 clockwise to separatethe arcing contacts 7, 8. As a result of the movement of shaft 31 andcam 60 mounted thereon spring 62 is allowed to act on the stem of piston20 to help actuate blast valve 14 to its open position and to maintainblast valve 14 open even upon dumping of the air from the upstream sideof piston 20.

After piston 48 of fluid motor 45 has passed a port 73 in its contactopening movement, air under pressure passes through port 73, pipe line106 to the under side of piston 103 arranged in cylinder 102. Piston 103and member 105 are actuated upward and push armature upward to rotatelever arm 91 counterclockwise. Push rod 92 is slidably mounted in a cap119 and is actuated by lever arm 91 to force pilot valve 84 closed,thereby allowing pressure to build up behind main valve member 83 toclose it. Once the pilot valve 84 has been closed by an external force,springs 86 and 101 are strong enough to hold it closed.

When coil 97 is energized, piston 103 of pole member is magneticallylocked or sealed in one of two possible positions. If the pressure inpipe line 106 is below a predetermined value piston 103 is in its lowerposition and the magnetic flux passing through casting 98 passes throughpole surfaces 112 and piston 103 to magnetically lock the piston 103 inits lower position. The magnetic flux in casting 98 attracts armature 95and draws it down to pole member 105, causing lever arm 91 to rotateclockwise and spring 101 to be compressed. Clockwise rotation of leverarm 91 removes the external force from the stem of the pilot valve 84.In the event that coil 97 remains energized after the contacts 7, 8

have separated a predetermined distance, air from pipe lines 35 and 44passes through fluid motor 45, port 73 in cylinder 47 into pipe line106. Fluid under pressure in pipe line 106 forces piston 103 andmagnetic pole member 105 up and away from the pole surface 112. As thepiston 103 reaches the upper limit of its travel the piston 103 issnapped into engagement and is magnetically sealed and locked in theupper position against the pole surface 111. The piston 103 remains inits upper position against the pole surface 111 as long as coil 97remains energized with a predetermined current.

The upward travel of the pole member 105 pushes armature 95 upward andby virtue of the counterclockwise rotation of lever arm 91 forces thepilot valve 84 closed. As the pilot tip 87 begins to throttle, spring101 forces closed the pilot valve 84 and holds its closed. Continuedenergization of the coil 97 holds piston 103 against the pole surfaces111 and lever arm 91 holds the pilot valve 84 closed even though thepneumatic pressure in line 106 is greatlyreduced.

In the event of a flick? operation of a control button which wouldenergize coil 97 only long enough to allow the pilot valve 84 to lift'and seal open, the pilot valve 84 would remain open until the valvemechanism 25 has gone through a complete operation. After the pilotvalve has opened, spring 101 is not strong enough to close the valve andcompressed air flowing through motor 45 and pipe 106 must raise piston103 and pole piece 105 to rotate counterclockwise lever arm 91 to movethe pilot valve 84 in valve closing direction to the point where thespring 101 takes over and completely closes the pilot valve 84 and themain valve member 83.

The circuit breaker arcing contacts are closed by energizing the coil 97of solenoid valve 63. V This valve operates in the same manner as valve25 to allow fluid under pressure from reservoir 6 through the main valvemember 83 to the fluid motor 64. The actuation of fluid motor 64 closesthe arcing contacts 7, 8.

Pipe lines 35 and 108 are connected to the lower side of casting 98 andactuate piston 103 of valve 63 upward to the lock pilot valve closedposition during a circuit breaker opening operation. Thus, if a closingoperation is initiated while the breaker is in the act of closing, theopening valve will take preference.

As shown and described the pilot valve 84 is actuated to closed positionafter a predetermined movement of piston 48 of fluid motor 45 on piston103 of solenoid operated valve 25. Thus, the pilot valves 25 and 63 are.controlled by fluid operated pistons, the positions of which arerelated to the positions of the arcing contacts 7, 8.

Although but one embodiment of the present invention has beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

Features disclosed but not claimed herein are claimed in applicationSerial No. 266,931, filed January 17, 1952, now Patent No. 2,689,317,granted Sept. 14, 1954 and in application Serial No. 264,370, filedJanuary 2, 1952, now Patent No. 2,778,379, granted Jan. 22, 1957 ofJulius W. Timmerman, the latter of which this application is a division.

It is claimed and desired to secure by Letters Patent:

1. In combination, a valve, valve holding means connected to said valvefor holding said valve closed against fluid under pressure,electromagnetic means including a coil, means defining a magnetic fluxpath linked with said coil comprising a core provided with a first polesurface and a second pole surface, a pole member engaging said firstpole surface and held against said first pole surface responsive toenergization of said coil, and an armature connected to said valveholding means and disposed in a first position to cooperate with saidpole member to define an air gap, said armature being responsive toenergization of said coil to move toward said pole member into a secondposition for actuating said valve holding means to cause fluid underpressure acting against said valve to open said valve, and means fordisengaging said pole member from said first pole surface and engagingsaid pole member with said second pole surface to cause said pole memberto engage said armature to return said armature to said first position.

2. In combination, a valve, valve holding means connected to said valvefor holding said valve closed against fluid under pressure,electromagnetic means including a coil, means defining a magnetic fluxpath linked with said coil comprising a core provided with a first polesurface and a second pole surface, a pole member engaging said firstpole surface and held against said first pole surface responsive toenergization of said coil, and an armature connected to said valveholding means and disposed in a first position to cooperate with saidpole member to define an air gap, said armature being responsive toenergization of said coil to move toward said pole member into a secondposition for actuating said valve holding means to cause fluid underpressure acting against said valve to open said valve, and pneumaticmeans for disengaging said pole member from said first pole surface andengaging said pole member with said second pole surface to cause saidpole member to engage said armature to return said armature to saidfirst position to cause said armature and said holding means to locksaid valve closed as long as a predetermined current flows through saidcoil.

3. In combination, a valve, said valve comprising a first surfacearranged to be permanently exposed to fluid under pressure and a secondsurface arranged to be exposed to fluid under pressure upon cracking ofsaid valve, valve holding means connected to said valve to hold saidvalve closed against fluid under pressure, electromagnetic meansincluding a coil, means defining a magnetic flux path linked with saidcoil comprising a core provided with a first pole surface and a secondpole surface, a pole member engaging said first pole surface and heldagainst said first pole surface responsive to energization of said coil,and an armature connected to said valve holding means and disposed in afirst position to cooperate wth said pole member to define an air gap,said armature being responsive to energization of said coil to movetoward said pole member into a second position for actuating said valveholding means to enable fluid under pressure to act on said firstsurface to crack said valve, the fluid under pressure upon cracking saidvalve acting on said second surface and actuating said valve to openposition, and fluid means for disengaging said pole member from saidfirst pole surface and engaging said pole member with said second polesurface to cause said pole member to engage said armature to return saidarmature to said first position, said pole member when in contact withsaid second pole surface abutting said armature to cause said armatureand said valve holding means to lock said valve in closed position aslong as a predetermined current flows through said coil.

4. In combination, a valve, said valve comprising a first surfacearranged to be permanently exposed to fluid under pressure and a secondsurface arranged to be exposed to fluid under pressure upon cracking ofsaid valve, spring means for biasing said valve in valve closingdirection, valve holding means connected to said valve to hold saidvalve closed against fluid under pressure, electromagnetic meansincluding a coil, means defining a magnetic flux path linked with saidcoil comprising a core provided with a first pole surface and a secondpole surface, a pole member engaging said first pole surface and heldagainst said first pole surface responsive to energization of said coil,and an armature connected to said valve holding means and disposed in afirst position to cooperate with said pole member to define an air gap,said pole member and said armature forming a part of the flux paththrough said core, said armature being responsive to energization ofsaid coil to move toward said pole member into a second position foractuating said valve holding means to enable fluid under pressure to acton said first surface to crack said valve, the fluid under pressure uponcracking said valve acting on said second surface and actuating saidvalve to open position, and fluid means for disengaging said pole memberfrom said first pole surface and engaging said pole member with saidsecond pole surface to cause said pole member to engage said armature toreturn said armature to said first position, said pole member when incontact with said second pole surface abutting said armature to causesaid armature and said valve holding means to lock said valve in closedposition as long as a predetermined current flows through said coil.

5. In combination, a valve, said valve comprising a first surfacearranged to be permanently exposed to fluid under pressure and a secondsurface arranged to be exposed to fluid under pressure upon cracking ofsaid valve, spring means for biasing said valve in valve closingdirection, valve holding means connected to said valve to hold saidvalve closed, said valve holding means being strong enough to hold saidvalve closed once it is closed but not strong enough to close said valveonce it is open, electromagnetic means including a coil, means defininga magnetic flux path linked with said coil comprising a core providedwith a first pole surface and a second pole surface, a pole memberengaging said first pole surface and held against said first polesurface responsive to energization of said coil, and an armatureconnected to said valve holding means and disposed in a first positionto cooperate with said pole member to define an air gap, said armaturebeing responsive to energization of said coil to move toward said polemember into a second position for actuating said valve holding means toenable fluid under pressure to act on said first surface to crack saidvalve, the fluid under pressure upon cracking said valve acting on saidsecond surface and actuating said valve to open position, and fluidmeans for disengaging said pole member from said first pole surface andengaging said pole member with said second pole surface to cause saidpole member to engage said armature-to return said armature to saidfirst position, said pole member when in contact with said second polesurface abutting said armature to cause said armature and said valveholding means to lock said valve in closed position as long as apredetermined current flows through said coil.

6. In combination, a valve, said valve comprising a first surfacearranged to be permanently exposed to fluid under pressure and a secondsurface arranged to be exposed to fluid under pressure upon cracking ofsaid valve, valve holding means connected to said valve to hold saidvalve closed, electromagnetic means including a coil, means defining amagnetic flux path linked with said coil comprising a core provided witha first pole surface and a second pole surface, a pole member biasedagainst said first pole surface and being movable from said first polesurface to said second pole surface to shift the flux path through saidcore, and an armature connected to said valve holding means and disposedin a first position to cooperate with said pole member to define an airgap, said armature being responsive to energization of said coil to movetoward sai d pole member into a second position for actuating said valveholding means to enable fluid under pressure to act on said firstsurface to crack said valve, the fluid under pressure upon cracking saidvalve acting on said second surface and actuating said valve to openposition, and fluid actuating means comprising a piston forming a partof said pole member for disengaging said pole member from said firstpole surface and engaging said pole member with said second pole surfaceto cause said pole member to engage said armature to return saidarmature to said first position,

said pole member when in contact with said second pole surface abuttingsaid armature to cause said armature and said valve holding means tolock said valve in closed position as long as a predetermined currentflows through said coil.

7. In combination, a valve, said valve comprising a first surfacearranged to be permanently exposed to fluid under pressure and a secondsurface arranged to be exposed to fluid under pressure upon cracking ofsaid valve, spring means for biasing said valve in valve closingdirection, valve holding means connected to said valve to hold saidvalve closed, said valve holding means being strong enough to hold saidvalve closed once it is closed but not strong enough to close the valveonce it is open, electromagnetic means including a coil, means defininga magnetic flux path linked with said coil comprising a core providedwith a first pole surface and a second pole surface, a pole memberengaging said first pole surface and held against said first polesurface responsive to energization of said coil, and an armatureconnected to said valve holding means and disposed in a first positionto cooperate with said pole member to define an air gap, said armaturebeing responsive to energization of said coil to move toward said polemember into a second position for actuating said valve holding means toenable fluid under pressure to act on said first surface to crack saidvalve, the fluid under pressure upon cracking said valve acting on saidsecond surface and actuating said valve to open position, and fluidactuating means comprising a piston forming a part of said pole memberfor disengaging said pole member from said first pole surface andengaging said pole member with said second pole surface to cause saidpole member to engage said armature to return said armature to saidfirst position, said pole member when in contact with said second polesurface abutting said armature to cause said armature and said valveholding means to lock said valve in closed position as long as apredetermined current flows through said coil.

8. In combination, a valve, said valve comprising a first surfacearranged to be permanently exposed to fluid under pressure and a secondsurface arranged to be exposed to fluid under pressure upon cracking ofsaid valve, valve holding means connected to said valve to hold saidvalve closed, electromagnetic means including a coil, means defining amagnetic flux path linked with said coil comprising a core provided witha first pole surface and a second pole surface, a pole member engagingsaid first pole surface and held against said first pole surfaceresponsive to energization of said coil, and an armature connected tosaid valve holding means and disposed in a first position to cooperatewith said pole member to define an air gap, said armature being biasedto said first position and magnetically attracted to a second positionby the magnetic flux of said core upon energization of said coil foractuating said valve holding means to enable fluid under pressure to acton said first surface to crack said valve, the fluid under pressure uponcracking said valve acting on said second surface and actuating saidvalve to open position, and means for disengaging said pole'member fromsaid first pole surface during energization of said coil and engagingsaid pole member with said second pole surface to cause said pole memberto engage said armature to return said armature to said first position,said pole member when in contact with said second pole surface abuttingsaid armature to actuate said armature against the magnetic field ofsaid coil and said valve holding means to lock said valve in closedposition as long as a predetermined current flows through said coil.

References Cited in the file of this patent UNITED STATES PATENTS1,406,333 Beach Feb. 14, 1922 2,327,366 Nampa Aug. 24, 1943 2,525,470Baker Oct. 10, 1950

